A storage using a flash memory is equipped with a plurality of memory chips, and drives the plurality of memory chips in parallel so as to improve data transfer performance. From the respective memory chips, physical blocks are collected to construct a virtual block of a logical block using the plurality of collected physical blocks. The logical block is a unit of management for erasing, wear leveling, and the like. From the respective physical blocks configuring the logical block, physical pages are selected. The plurality of selected physical pages configures a unit of management referred to as a logical page. The logical page is a write unit on a memory system. Constructing the logical block for driving the plurality of physical blocks in parallel speeds up the data transfer. Similarly, constructing the logical page for driving the plurality of physical pages in parallel speeds up the data transfer.